Ruth Fielding at the War Front; or, The Hunt for the Lost Soldier

It was a midwinter day, yet the air was balmy. The trees were bare-limbed but with a haze clothing them in the distance that seemed almost that of returning verdure. The grass, even in mid-winter, showed green. A bird sang lustily in the hedge.
Up the grassy lane walked a girl in the costume of the active Red Cross worker—an intelligent looking girl with a face that, although perhaps not perfect in form, was possessed of an expression that was alluring.
Neither observant man nor woman would have passed her, even in a crowd, without a second glance. There was a cheerful light in her eye and a humorous curve to her not too-full lips that promised an uplifting spirit within her even in serious mood.
It seemed as though this day—and its apparent peace—must breed happiness, although it was but a respite in the middle of winter. The balmy air, the chirrup of the bird, the far-flung reaches of the valley which she could see from this mounting lane, all delighted the senses and soothed the spirit.
Suddenly, with an unexpectedness that was shocking, there was a tremor in the air and the echo of a rumbling sound beneath the girl's feet. The crack of a distant explosion followed. Then another, and another, until the sound became a continual grumble of angry explosions, resonant and threatening.
The girl did not stop, but the expression of her face lost its cheerfulness. The song of the bird was cut off sharply. It seemed as though the sun itself began drawing a veil over his face. The peaceful mood of nature was shattered.
The girl kept on her way, but she no longer stepped lightly and springily. Those muttering guns had brought a somber cloak for her feelings—to her very soul.
Somewhere a motor began to hum. The sound came nearer with great rapidity. It was a powerful engine. It was several seconds before the girl looked up instead of along the road in search of the seat of this whirring sound.
There shot into view overhead, and flying low, an aeroplane that looked like a huge flying insect—an enormous armored grasshopper. Only its head was somewhat pointed and there, fixed in the front, was the ugly muzzle of a machine gun. The airplane flew so low that she could see the details.